In some engines requiring air-assisted fuel injectors, the injectors are mounted in an air-assist manifold that serves all injectors. In other engines, assist air may be fed to each injector through its own tube. In both, there is a need for adaptation to the engine so that leakage is avoided.
A number of patents disclose various forms of individual adapters for individually mounting an air-assist type fuel injector on an engine. For example, please refer to U.S. Pat. No. 5,218,943. One known adapter comprises a metal receptacle for receiving the nozzle end of a fuel injector and a metal tube that is joined by a process such as brazing, welding, etc. to a hole in the sidewall of the receptacle for communicating assist air to an axially sealed zone inside the receptacle surrounding assist air entrances of the air-assist nozzle.
While the use of metal pads in an adapter may be acceptable, care must be taken during the fabrication process to guard against the creation of sharp edges, burrs, weld spatter, etc., which may have the potential for damaging seals that are necessary in order to provide proper sealing of the injector to the adapter and of the adapter to the engine. Likewise, care must be exercised to assure compliance with the typically tight tolerances that are involved in fitting to an injector and to an engine. Naturally, these measures may be reasonably anticipated to add to the cost of the adapter and its installation. Avoidance of these measures is apt to make an air-assist fuel injection system more competitive.
Development of a fuel injection system for an engine may involve substitution of parts in order to arrive at the best possible combination. The ability to quickly and conveniently make substitutions of fuel injector system components should contribute to a decrease in the development time and should enhance the ability to substitute fuel injector system components at anytime, such as after the engine has gone into service.
Briefly, the invention involves the creation of an adapter for adapting an air assist nozzle of a fuel injector to an engine by using a molding process like injection molding to create a one-piece molded plastic adapter. The resultant adapter possesses certain structural features not found in earlier adapters. One important feature is the snap-on, snap-off attachment of the adapter to an air-assist fuel injector. This feature is provided by integrally formed catches. The use of plastic injection molding also offers the potential for avoiding sharp edges, burrs, etc. Because the adapter is one-piece, it does not have to be fabricated by joining several individual components together.
The foregoing features, advantages, and benefits of the invention, along with additional ones will be seen in the ensuing description and claims which are accompanied by a drawing that shows a presently preferred embodiment of the invention according to the best mode presently contemplated for carrying out the invention.